Gun barrel



FIG. 1 is a right side view of a gun barrel showing our new design;

FIG. 2 is a left side view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a front view thereof;

FIG. 6 is rear view thereof;

FIG. 7 is a front perspective view thereof; and,

FIG. 8 is a rear perspective view thereof. 

CLAIM The ornamental design for a gun barrel, as shown. 